1. Field of the Invention
The present invention relates generally to plethysmographic devices and more particularly to plethysmographic devices adapted for use with laboratory animals.
2. Background of the Invention
Generally, plethysmography relates to a process for measuring variations in volume of a particular organ, part, limb or body. Presently, there are a number of plethysmographic devices known in the art which are used for many specific purposes. One type are adapted for measuring various pulmonary parameters of animals during laboratory testing procedures. For example, the plethysmograph in such applications can be utilized to determine different aspects of pulmonary function, for example to measure lung volumes, residual volume of the lung, airway resistance, and pulmonary blood flow. In operation, volume and/or pressure changes are monitored over a particular time period for determining the respective pulmonary characteristics in accordance with Boyle's law (PV=K). Generally, plethysmographic devices of this type comprise sealed containers which are adapted to receive the body of the animal therein for testing. In particular, a removable section is included in the container which allows access to the interior of the device.
In addition, it is oftentimes desirable that the animal is anesthetized and tracheotomized prior to operation within the plethysmographic container. In this regard, a flat bed-like portion is utilized in order to support the animal within the container during operation. Further, numerous hook-up fittings can also be provided within the container in order to allow access to the animal after the device has been sealed. For example, in many instances it is desirable to provide a cardiovascular line or other monitoring apparatus in communication with the animal.
One problem with such prior art devices, however, occurs as a result of the seal of the device. Generally, the removable section of the plethysmographic container is connected by a seal to the rest of the container during operation. However, such seals are typically of the end-on or face-seal type, which require a cumbersome latching mechanism for joining the two parts of the container. Another problem occurs when the container is in the opened position in order to gain access To the animal contained therein. Specifically, an additional support is required in this position in order to stabilize the bed portion of the device. Still another problem is that it is oftentimes difficult to access the various small tubing ports which may be located in a recess in the container wall. Specifically, connecting the numerous small tubings, which are utilized for monitoring the animal, to these tubing ports, all within the space occupied by the head of the animal, can be a daunting task for the individual performing the testing procedure. Another problem occurs as a result of bodily excrement produced by the animal during the course of an experiment, when the container is in its sealed state. Specifically uncontained accumulation of such excrement, which may be excessive due to the substances to which the animal is subjected, makes cleaning of the experimental container a distasteful and difficult task.
The present invention has has been developed in view of the foregoing and to overcome the deficiencies of the prior art.